Method of strengthening structural members



1935- A. G. LEAKE 2,000,599 I METHOD OF STRENGTHENING STRUCTURAL MEMBERS Filed Dec. 30, 1951 k i l zf/ mp /5 k M 2 Fz' ii V l Patented May 7, 1935 UNITED STATES PATENT OFFICE METHOD OF STRENGTHENING STRI JC TURAL MEMBERS 3 Claims.

This invention relates to a method and means of strengthening structural members, particularly members'held together by rivets, and has for an object to provide an improved method and means of strengthening .these members either.

when therivet heads have been destroyed or deteriorated, or where it is desirable to increase the section of the members and therefore their load carrying capacity without the necessity of tearing down the members or removing them from their normal positions.

With the foregoing and other objects in view,

the invention consists in a novel method and means as will be more fully disclosed in connection with the accompanying drawing.

In this drawing:

Fig. 1 is a side elevation of a portion of a built-up girder or beam showing the application of my invention;

Fig. 2 is a vertical section substantially on line 2-2 of Fig. 1;

Fig. 3 is a top plan view;

Fig. 4 is a detailed section on an enlarged scale substantially on line 4- -4 of Fig. 3: and

Fig. 5 is a similar section showing a modified construction.

In the drawing the invention is shown as applied to a built-up beam or girder comprising a web plate Ill and angle members ll secured to the upper and lower edges of the web It! by rivets l2. To the outer surfaces of the horizontal flanges of the agles H are secured longitudinal plates l3 by means of the rivets M. It is, however, to be understood that this particular structure is shown merely for the purposes of illustration, and that the invention is equally applicable for strengthening other structural members, such as beams, trusses, columns, chords for trusses, webs for plate girders, other types of built-up girders, and the like. a

In carrying out the invention the old rivet heads are removed flush with the surfaces of the members secured thereby. Thus if the iiange plates are to be strengthened the outer heads of of the rivets l4 indicated in dotted lines at l5, Figs. 4 and 5, are removed flush with the surface of the plates I3. This can be done by cutting off or burningoff the heads of the rivets, and of course, it will'be understood that the surface of these plates l3 will be cleaned to remove paint, scale and rust by. any suitable means such as an acetylene oxygen torch,. scraping and cleaning with a; wire brush, or any other suitable means. Anew structural strengthening member, such as a plate It or II is provided with openings or holes l8 of a spacing corresponding with the spacing'of the rivets and preferably corresponding with the size of the shanks IQ of the rivets left in the old structure. This new strengthening member is thenapplied to the old structure with'the openings IS in alignment with the shanks of the rivets, and then is welded ,through the holes in the new member to the shanks iii of the rivets as indicated at 20, the weld metal being thoroughly welded to the sides of the openings and to the ends of the rivet shanks, and the opening is preferably filled up with this weld metal to or flush with the outer surface 2| of the new member. This gives the value of the full diameter of the rivet in shear between the plates l5 and I3.

If it is desired to have the value of the rivet head I can carry up the shank of the rivet with the weld metal and build up a head 22 with this weld metal outside the new member l8 as indicated in Fig. 5.

After the rivets have been welded, the edges of the new structural member can be welded as required. Thus at the top of Figs. 1 and 2 where the new cover plate I6 is shown asbeing of less width than the plate IS, the edges of this plate are welded to the surface of the plate l3 by adding weld metal as indicated at 23. At the lower part of the structure as shown in Figs. 1 and 2 where the new plate I! is of greater width than the old'plate [3, the edges of the plate 13 can be welded to the surfaces of the plate I! in the same manner as indicated at 24.

It will be evident that although I have shown the strengthening members It and I! as being cover plates the invention is equally applicable to' the securing of other types. or shapes of strengthening members, such as angles, channels, beams, and the like, It'will also be evident that the members can be added and the full strength of the rivets restored without removing the rivets or tearing down the old structure, and the work can be done while the structure is in position or even under load, thus greatly reducing the cost of increasing the strength of the old structure over the old methods.

Having thus set forth the nature of my invention, what I claim is:

1. The method of strengthening structural members secured by rivets which comprises removing the heads of the rivets on one side of av member while the member is in position in a built up structure of structural members, placing a reinforcing plate member provided with openings with a spacing correspondmg with the spacing of the rivets against the first member over the rivet shanks, welding the plate member to the shanks through the openings by adding weld metal to the shanks and the sides of the openings to build up the shanks, and welding edges of one of the members to the other member.

2. The method of strengthening structural members secured by rivets which comprises removing the heads of the rivets on one side of a member while the member is in position in a built up structure of structural members, placing a reinforcing member against the first member having holes of a spacing to correspond with the spacing of the rivets and with the holes in alignment with the rivet shanks, welding the reinforcing member to the rivet shanks through said holes by adding weld metal to the shanks and the sides of the holes to build up the shanks, and welding edges of one of the members to the other member. v

3. The method of strengthening structural members secured by rivets which comprises removing the heads of these old rivets on one side of a member while the member is in its position in a built up structure of structural members, placing a reinforcing member provided with holes of a spacing corresponding with the spacing-of the rivets against the first member over the rivet shanks and with the holes in I alignment with said shanks, and welding the reinforcing member to the rivet shanks through said holes by adding weld metal to the shanks and the sides of the holes to build up the shanks.

ARTHUR G. LEAKE- 

